darcs patch: [PROOF OF CONCEPT] build readline package with libedit

[Simon Marlow]

Judah Jacobson wrote:
> I've actually put together a readline-compat package like you described:
> 
> http://code.haskell.org/readline-compat

This is not the way to go, IMO.  As Manuel said, we don't want packages 
with licenses that depend on the way the package is built.  The 
readline-compat package above has this problem, and the only way to fix it 
is to make its license GPL.  But presumably that's exactly what you don't 
want to do, because the purpose of using editline is to avoid the GPL.

Packages which want to use either editline or readline should say so in 
their .cabal files, we cannot abstract this choice into a package of its own.

Cheers,
	Simon